Atriplex dioica

Rafinesque

Amer. Monthly Mag. & Crit. Rev. 2(2): 119. 1817.

Common names: Thickleaf orach
IllustratedEndemic
Synonyms: Atriplex patula var. subspicata (Nuttall) S. Watson Atriplex subspicata (Nuttall) Rydberg
Treatment appears in FNA Volume 4. Mentioned on page 323, 324, 333, 334.

Herbs, monoecious, typically erect and often branching, 3–15 dm; stems green or striped, angular. Leaves opposite or subopposite at least proximally; petiole 1–3 cm; blade strongly 3-veined from near base, lanceolate to linear-lanceolate or often triangular-ovate or lanceovate, 30–125 × 25–60 (–80) mm, thickened, basal or subbasal lobes spreading to mainly antrorse, obtuse, blade otherwise entire to sparingly dentate, typically scurfy. Flowers in terminal or terminal on lateral branches, in spiciform spikes, 2–9 cm, naked except at base. Fruiting bracteoles green, blackening in age, sessile, veined or veins obscure, broadly triangular to ovate, 3–10 mm, thick, usually longer than wide, base truncate to obtuse, margin united at base, apex acute lateral angles entire or with short, sharp teeth, faces smooth or with 2 tubercles, with an inflated inner spongy layer. Seeds ellipsoid, wider than long, dimorphic: brown, 1.5–3 mm wide, flattened at base, or black, 1–2 mm wide, shiny; radicle inferior. 2n = 36, 54.


Phenology: Flowering summer–fall.
Habitat: Sea beaches, other saline habitats
Elevation: 0-1500 m

Distribution

V4 637-distribution-map.gif

Alta., B.C., Man., Nfld. and Labr. (Nfld.), N.S., Nunavut, Ont., Que., Sask., Yukon, Ariz., Calif., Colo., Idaho, Iowa, Kans., Maine, Mass., Minn., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Dak., Okla., Oreg., R.I., S.Dak., Utah, Wash., Wyo.

Discussion

The distribution of the species is evidently bipartite, with an eastern coastal series extending northward mainly from New Jersey to Newfoundland and along the St. Lawrence seaway, and perhaps extending to James Bay of Hudson Bay. The western grouping lies mainly west of the 95th meridian of longitude, where it has been collected since early historical times to the present in saline marshes or other saline sites from the Yukon Territory and Northwest Territories, southward to southern California, northern Arizona, northern New Mexico, and Oklahoma.

Rafinesque gave the following information: “Stem upright angular branched, leaves petiolate, deltoid, acute, thick, scaly, the proximal opposite toothed, the distal alternate, hastated, entire: flowers dioical glomerate, male spiked naked, female unequal, sepals deltoid, warty-crested.”

The name Atriplex dioica Rafinesque antedates Chenopodium subspicatum Nuttall by half a year, being published in December 1817. Hence, it is the correct name for the widely ranging species, which has passed most recently under the name A. subspicata. Nuttall’s description of the habitat of Chenopodium subspicatum is: “In saline soils around Mandan Village, Missouri,” a designation of habitat that applies to this day.

The species forms a mirror-image set of specimens with the remarkably similar Atriplex prostrata, from which it may be distinguished in most cases by the thickened, merely ovate to lanceolate leaf blades, and less commonly but in some localities exclusively triangular-hastate to lanceolate, mostly scurfy and prominently 3-veined leaf blades. In some specimens, including the types of both Chenopodium subspicatum and Atriplex carnosa, the blades bear a hastate lobe at or above the base and sometimes match triangular-hastate profile of A. prostrata. The leaves of A. prostrata are typically thin-textured, green, not scurfy, and the veins of the blade are obscure. I. J. Bassett et al. (1983) disallowed within A. dioica (as A. subspicata) any but those with lanceolate blades, including those with the proximalmost leaves with a pair of subbasal hastate lobes. However, there are numerous specimens in which the blades are thickened and transitional in that regard to the triangular-hastate profile as in A. prostrata. Certainly those specimens with triangular or triangular-hastate leaves taken prior to the introduction of A. prostrata sometime late in the nineteenth or early twentieth century, clearly belong to the indigenous A. dioica. Whether there are intermediates between diploid (2n = 18) A. prostrata and tetraploid or hexaploid (2n = 36, 54) A. dioica is not known. There does not seem to be any consistent feature or combination of features by which all specimens can be assigned to one or the other of the two taxa. It seems probable, however, that A. prostrata is a late introduction from Europe, and that it, along with the related A. heterosperma, is now invading habitats previously occupied exclusively by the indigenous A. dioica.

Selected References

None.

Lower Taxa

None.

No values specified."thick" is not a number.

... more about "Atriplex dioica"
veined +  and sessile +
blackening +  and green +
Stanley L. Welsh +
Rafinesque +
slippery +
aromatic +
truncate +  and obtuse +
entire +  and sparingly dentate +
6 cm60 mm <br />0.06 m <br /> (8 cm80 mm <br />0.08 m <br />) +
3 cm30 mm <br />0.03 m <br /> (12.5 cm125 mm <br />0.125 m <br />) +
lanceovate +, triangular-ovate +, often +, lanceolate +  and linear-lanceolate +
2.5 cm25 mm <br />0.025 m <br /> (6 cm60 mm <br />0.06 m <br />) +
persistent +  and deciduous +
reddish-brown +, black +, brown +  and green +
linear +  and deltoid +
3-5-parted +
Thickleaf orach +
Alta. +, B.C. +, Man. +, Nfld. and Labr. (Nfld.) +, N.S. +, Nunavut +, Ont. +, Que. +, Sask. +, Yukon +, Ariz. +, Calif. +, Colo. +, Idaho +, Iowa +, Kans. +, Maine +, Mass. +, Minn. +, Mont. +, Nebr. +, Nev. +, N.H. +, N.J. +, N.Mex. +, N.Dak. +, Okla. +, Oreg. +, R.I. +, S.Dak. +, Utah +, Wash. +  and Wyo. +
0-1500 m +
tuberculate +  and smooth +
unisexual +  and bisexual +
2 cm20 mm <br />0.02 m <br /> (9 cm90 mm <br />0.09 m <br />) +
not +  and connate +
enlarged +
Sea beaches, other saline habitats +
bladderlike +
terminal +  and axillary +
subopposite +  and opposite +
deciduous +  and persistent +
spreading +  and mainly antrorse +
not winged +  and winged +
entire +  and serrate +
toothed +  and entire +
inferior +, half-inferior +  and superior +
crassinucellate +  and bitegmic +
campylotropous +
1 +  and single +
persistent +  and deciduous +
(1-)3-5-lobed +
papery +  and chartaceous +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
Flowering summer–fall. +
Amer. Monthly Mag. & Crit. Rev. +
bulbous +  and taprooted +
fusiform +
fleshy +  and fibrous +
verrucate +  and striate +
black +  and brown +
ellipsoid +  and flattened +
Illustrated +  and Endemic +
cylindric +
3 +  and 5 +
opposite +  and alternate +
striped +  and green +
succulent +
sessile +  and petiolate +
reduced;small +
horizontal +  and vertical +
verrucate +
Atriplex patula var. subspicata +  and Atriplex subspicata +
Atriplex dioica +
Atriplex sect. Teutliopsis +
species +
dicotyledonous +
usually longer than wide +
broadly triangular +  and ovate +
0.3 cm3 mm <br />0.003 m <br /> (1 cm10 mm <br />0.01 m <br />) +